ENTANGLED DYNAMICS OF HEALING END-GRAFTED CHAINS AT A SOLID POLYMER INTERFACE/

We present theoretical calculations of the dynamics of end-grafted cha ins on a solid substrate approaching their equilibrium conformations w ithin a compatible network placed on the substrate. We assume that T m uch greater than T-g and that the motion is dominated by entanglements . The problem has two limits corresponding to high and low surface-gra fting density of the chains. In the latter case some chemical affinity between network and chain is required to ensure penetration. We make detailed calculations on each limit and find that in both cases there are three dynamical regimes: (i) fast Rouse-like penetration of part o f the grafted chain, (ii) retraction of the free ends and (iii) diffus ive dynamics of a slow variable. Both adhesive strength and interfacia l width are predicted to grow on long timescales varying exponentially with molecular weight.